‘Stranger Things’ Season 4 Is the Most Supersized Ever 

"Volume 1, which comes out May 27, will feature the first seven episodes of the season. And the remaining episodes will come with Volume 2, which arrives July 1, for a total of nine — NINE — supersized episodes of Stranger Things headed your way in a matter of days. Those nine episodes total roughly 13 hours of Upside Down goodness. Better yet? The final two episodes of Volume 2 clock in at nearly four hours long. (For the real geeks out there, Episode 407 is 1 hour, 38 minutes; Episode 408 is around 1 hour, 25 minutes; and 409 is almost two and a half hours.)"

So, to recap:
Volume 1 on May 27th: Episodes 1-7, ~9 hours
Volume 2 on July 1st: Episodes 8-9, ~4 hours